MUSCLE AND NERVE 



45 



you will obtain a summation. Load the muscle with a weight of 10 

 grams, and move the drum a distance of about 5 mm. to the left. Re- 

 peat the stimulation. Continue to load the muscle successively with 



O 10 ZO 30 K) SO to 10 80 <JO 100 



FIG. 24. INFLUENCE OF LOAD. 

 This muscle has been successively loaded with 10-gram weights. 



10-gram weights until it ceases to show an appreciable contraction. 

 Observe the general outline of the curve obtained, and formulate a 

 general rule regarding the height of the contraction and the load. 



FIG. 25. DIAGRAM OF WORK-ADDER. 



A, Wheel which is turned by muscle M in direction of arrows. It i. held in place by 

 brake B. Each contraction of muscle raises weight W. 



8. Muscular Work. Obtain in millimeters the values for: L, the 

 total length of the writing lever, I, the distance from its axis to the 

 point of attachment of the muscle, and H, the height of each contraction. 



In accordance with the formula, L : H :: I : h, compute the height 

 to which the weight has been lifted during each contraction (h). The 



